The medical device industry produces a wide variety of electronic and mechanical devices such as neurological stimulators, therapeutic substance infusion pumps, pacemakers, and defibrillators for treating patient medical conditions such as pain, movement disorders, functional disorders, spastisity, cancer, and cardiac disorders. Medical devices can be configured to be surgically implanted or connected externally to the patient receiving treatment and can be used either alone or in combination with pharmaceutical therapies and surgery to treat patient medical conditions. For certain medical conditions, medical devices provide the best and sometimes the only therapy to restore an individual to a more healthful condition and a fuller life. One type of medical device is an implantable neurological stimulation system typically includes a neurostimulator, an electrical stimulation lead, and an extension such as shown in Medtronic, Inc. brochure “Implantable Neurostimulation System” (1998). An implantable neurological stimulation system delivers electrical pulses to tissue such as neurological tissue or muscle to treat a medical condition.
Electrical stimulation leads can be configured as surgical leads that require an incision for implantation and as percutaneous leads that are implanted through a needle or introducer. Surgical leads are typically less constrained in their shape because the incision used for implantation can be easily varied according to the surgical lead shape. Percutaneous leads are typically constrained in their shape because of the requirement to be inserted through a needle or introducer. Implantation of percutaneous leads is shown in Medtronic, Inc. brochure Medtronic Percutaneous Implant Guide. It is difficult to implant a percutaneous lead in close combination with another percutaneous lead because it is difficult to coordinate the mechanical relationship between more than one percutaneous lead. It is also difficult to accommodate multiple lead bodies within a needle or introducer.